Tire Pressure

The pressure on the sidewall is the "maximum" pressure that equates to the maximum load the tire is rated for (usually near 2000 pounds). So, in regular driving, you need much less pressure. Check your VIN sticker for the recommended pressure for stock tires (likely either 28" or 30"), open the drivers door and you should see it on the side of the dash. 30-35 will be fine for your tires, but I might run more on the 30psi side to help the tires wear a little more evenly (slightly more on the sides to compensate for the prior wear). If you've got a bit more weight on the Jeep than stock (skid plates, steel bumpers with a winch, or just loaded heavy for a weekend trip), then you can run more on the 35psi side. I'd never run more than 40psi because you'll only be using the middle tread, like you found out.

In a similar vein, when you go offroad, you'll want to lower the pressure much more... down to the 15-20psi range for better traction and handling. Especially on the beach with soft sand. The side will spread out a little more and distribute the weight better for sand, and give more biting surface for rocks along with making the tires less susceptible to damage.

Quote from Doug

Thanks. That’s what I thought but wanted to make sure there wasn’t something I was missing ... particularly since they are bigger tires than I am used to. I’m not sure what the previous owner was thinking.

Pretty often, shops will do that too. Just put air in the tire until it "looks good"... Very common with bigger tires, too. I think a member here had her 33" tires at nearly 60psi from a shop and noticed that the handling was pretty crazy. Dropped down to a proper pressure and handled much better.